This invention relates to an exposure apparatus for use in the manufacture of semiconductor circuit devices and, more particularly, to an exposure apparatus for transferring a pattern of a mask onto a wafer.
Various types of exposure apparatuses have been developed for the manufacture of semiconductor circuit devices such as integrated circuits (ICs), large scaled integrated circuits (LSIs), etc. Each of such exposure apparatuses includes its own light source for providing an exposure beam by which a circuit pattern formed on a mask or reticle is irradiated so that the circuit pattern is transferred onto a wafer having a photoresist coating.
Also as is well known, the exposure apparatus mass-produces wafers having printed circuit patterns through the repetition of various working steps such as transportation of the wafer to the exposure stage, alignment between the mask and wafer, exposure of the wafer to the mask pattern, discharging the wafer from the exposure stage, etc.
Thus, the exposure step is merely a part of the working steps necessary for printing the circuit pattern onto wafer. Nevertheless, each the current exposure apparatus has its own light source for providing the exposure beam and this light source is continuously energized for the sake of stabilization of the exposure beam. During the working steps other than the exposure step, e.g. during the alignment step, a light blocking member such as a shutter is used to prevent exposure of the wafer resting on the exposure stage.
For this reason, each exposure apparatus becomes necessarily bulky, requiring a large space. This is inconvenient, since usually a plurality of such exposure apparatuses are juxtaposed in a semiconductor device manufacuring factory. In addition, consumption of energy is excessive because the exposure light source is always energized even during the steps other than the exposure step.